.user-chapter-detail {
  min-height: 100vh;
  background: var(--background-secondary);
}

/* Header */
.detail-header {
  background: linear-gradient(135deg, var(--primary-blue) 0%, var(--primary-blue-dark) 100%);
  color: white;
  padding: 3rem 2rem;
  margin-bottom: 3rem;
}

.header-content {
  max-width: 1200px;
  margin: 0 auto;
}

.back-btn {
  margin-bottom: 2rem;
  background: rgba(255, 255, 255, 0.15);
  color: white;
  border: 1px solid rgba(255, 255, 255, 0.3);
}

.back-btn:hover {
  background: rgba(255, 255, 255, 0.25);
  border-color: rgba(255, 255, 255, 0.5);
}

.chapter-info h1 {
  font-size: 2.5rem;
  font-weight: 600;
  margin: 0 0 0.75rem 0;
}

.chapter-info p {
  font-size: 1.125rem;
  margin: 0;
  opacity: 0.95;
}

/* Models Section */
.models-section {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 2rem 4rem;
}

.section-header {
  text-align: center;
  margin-bottom: 3rem;
}

.section-header h2 {
  font-size: 2rem;
  font-weight: 600;
  color: var(--text-primary);
  margin: 0 0 0.5rem 0;
}

.section-subtitle {
  font-size: 1rem;
  color: var(--text-secondary);
  margin: 0;
}

.models-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 1.5rem;
}

.model-card {
  padding: 2rem;
  cursor: pointer;
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.model-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 4px;
  height: 0;
  background: var(--primary-blue);
  transition: height var(--transition-base);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
}

.model-card:hover::before {
  height: 100%;
}

.special-badge {
  width: fit-content;
}

.model-title {
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--text-primary);
  margin: 0;
}

.model-description {
  color: var(--text-secondary);
  font-size: 0.875rem;
  line-height: 1.6;
  margin: 0;
  flex: 1;
}

.model-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-top: 1rem;
  border-top: 1px solid var(--border);
  margin-top: auto;
}

.model-date {
  display: flex;
  align-items: center;
  gap: 0.375rem;
  color: var(--text-tertiary);
  font-size: 0.875rem;
}

.model-arrow {
  color: var(--primary-blue);
  opacity: 0;
  transform: translateX(-10px);
  transition: all var(--transition-base);
}

.model-card:hover .model-arrow {
  opacity: 1;
  transform: translateX(0);
}

/* Empty State */
.empty-models {
  grid-column: 1 / -1;
  text-align: center;
  padding: 4rem 2rem;
  color: var(--text-tertiary);
}

.empty-icon {
  color: var(--gray-300);
  margin-bottom: 1rem;
}

.empty-models p {
  font-size: 1rem;
  margin: 1rem 0 0 0;
}

/* Loading & Error States */
.loading-spinner,
.error-state {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 60vh;
  gap: 1rem;
}

.spinner-icon {
  color: var(--primary-blue);
  animation: spin 1s linear infinite;
}

.error-icon {
  color: var(--error);
}

.error-state p {
  color: var(--error);
}

/* Responsive */
@media (max-width: 768px) {
  .chapter-info h1 {
    font-size: 2rem;
  }

  .chapter-info p {
    font-size: 1rem;
  }

  .section-header h2 {
    font-size: 1.5rem;
  }

  .models-grid {
    grid-template-columns: 1fr;
  }
}
